Staged condensation of coal tar was studied with a three-staged condensation system (first stage S1, 100–300 °C; second stage S2, 30–70 °C; third stage S3, 0 °C) to perform on-line preliminary removal of dust and fundamental fractionation of tar components. The dust and heavy components are predominantly distributed in S1. The polycyclic aromatic hydrocarbons are abundant in S1. Aliphatics and monocyclic phenols are abundant in S2, and the tar in S3 is rich in aliphatics and monocyclic aromatic hydrocarbons. With increasing S2 temperature from 30 to 70 °C, the total organics in the water phase in S2 and S3 are least at an S2 temperature of 50 °C, which is advantageous for post-treatment of wastewater.
- Coal tar
- Staged condensation